1. Technical Field
The present invention relates to a recording medium for recording digital data therein, and specifically to a recordable-type recording medium.
2. Background Art
One of typical methods for distributing digital contents of movies or the like is to distribute DVD-ROM discs with the digital contents recorded thereon, where DVD stands for Digital Versatile Disc.
In such a content distribution using DVD-ROM discs, content data conforming to the DVD-Video standard and protected by CSS (Content Scrambling System) are recorded onto the DVD-ROM discs. The CSS is a system that has been introduced to prevent unauthorized copy of contents. Currently, popular DVD players on the market are incorporated with a mechanism for achieving conformation to the CSS rules.
Currently under consideration as a content distribution method other than the above-described one using DVD-ROM is a system in which contents are downloaded using kiosk terminals installed in shops such as convenience stores.
The kiosk terminals are connected via a network with a server which stores contents therein. On a kiosk terminal, a user selects a content to purchase and inserts a recordable blank disc into the kiosk terminal. The kiosk terminal obtains the selected content from the server, and records the obtained content onto the blank disc. The content is subjected to some measures for copyright protection before it is recorded onto the disc.
In the above-described system, DVD-R, which is currently a mainstream recordable-type recording medium, may be used as the blank disc.    Patent Document 1: Japanese Patent Application Publication No. 2004-246990
In the above-described system, when DVD-R is used as the blank disc and the CSS is adopted as the copyright protection technology, expected is a problem that the content recorded on a DVD-R disc cannot be played back by conventional DVD players.
This is because the conventional DVD players are incorporated with a mechanism for achieving conformation to the CSS rules, and the mechanism regards a content recorded on a DVD-R disc, which has been inserted into such a conventional DVD player, as an unauthorized copy and prevents the DVD player from playing back the content when the content is protected by the CSS.
However, when the mechanism was created, CSS-protected contents were generally expected to be distributed on the discs. Therefore, with the above-described system in which a kiosk terminal receives a content and writes the received content onto a blank disc, the following inconveniences are expected to occur.
The kiosk terminal is licensed to write a CSS-protected content onto a DVD-R disc. On the other hand, a user, who had purchased a CSS-protected content and made the kiosk terminal write the content onto a DVD-R disc, would find that the content cannot be played back by a conventional DVD player that the user has. It would, however, be difficult to request all the users who wish to use the service via the kiosk terminal, to purchase a new DVD player that can play back the CSS-protected content recorded on the DVD-R disc.
Such an inconvenience might prevent the spread of the new content distribution system.
An object of the present invention is therefore to provide a recordable-type recording medium that enables a conventional DVD player to play back a content protected by the CSS that is recorded on the recordable-type recording medium itself, and to provide a data recording device, a data playback device, and a data recording method for the recordable-type recording medium.